Crossflow mower with automatic brake/sharpener

ABSTRACT

A mower of the cross-flow blower type has clutch means for engaging the motor with the rotor and disengaging the motor therefrom. One wall section of the blower conduit has an abrasive panel facing the rotor and is mounted for movement between a moving position in which the abrasive panel is spaced from the rotor and a brake/sharpening position in which the panel is contacted by the rotor blades. Means are provided for automatically moving the abrasive panel to the brake/sharpening position when the clutch means is disengaged and to the mowing position when the clutch means is engaged. Advantageously the abrasive panel is on a portion of the upper wall section which is close to the rotor and forms the front vortex breaker of the blower conduit. The wall section carrying the abrasive panel may be pivotally mounted or, advantageously, resiliently attached to the adjacent portion of the blower conduit. An eccentric rod may be employed for moving the wall section and abrasive panel.

REFERENCE TO OTHER APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.741,132 filed Nov. 11, 1976.

BACKGROUND OF THE INVENTION

The present invention relates to mowers of the cross-flow blower typeand provides an automatic brake/sharpener for such mowers.

Mowers of the cross-flow blower type are described in my U.S. Pat. No.3,673,773 and comprise a cylindrical reel having a plurality of spacedblades horizontally mounted on a carriage with the reel axis extendinglaterally of the carriage. A blower conduit cooperates with the reel toform a blower of the cross-flow or transverse-flow type. The outerleading edges of the blades are sharp to form cutting edges. No bedknife or shear plate is employed. In the preferred arrangements the reelrotates in a direction such that the lower blades move in the forwarddirection with respect to the normal direction of travel of the mower,and the outer edges of the blades are forwardly hooked.

In mower operation air is drawn into the blower from in front of themower and draws the grass toward the forwardly moving lower blades sothat the grass is cut effectively. The grass clippings are dischargedfrom the outlet of the blower and may be directed toward the ground,discharged to the side, or collected in a grass catcher.

In a cross-flow blower air is drawn into the rotor at the inlet region,passes through the interior of the rotor, and then passes out of therotor at the outlet region. Thus the air passes through the blades twicein a direction transverse to the rotor axis. Vortex components aroundthe blades are involved in the functioning of the blower.

In my U.S. Pat. No. 3,818,684 certain improvements are describedincluding a forward extension on the housing which causes an auxiliaryvortex to be developed.

In my application Ser. No. 741,132, supra, improvements are describedfor reducing blower noise while preserving good mowing performance, andeven enabling enhanced performance. In the specific embodiments of FIGS.1-3 other features are described in order to illustrate a preferredmower construction. Novel blade structures are described and the term"rotor" is employed. The term "rotor" is used herein to include suchstructures as well as the structures of U.S. Pat. No. 3,673,773, etc.

In order to cut grass cleanly, with minimum fraying, the cutting edgesof the blades should be reasonably sharp. This is also true ofconventional types of mowers such as rotary mowers and reel mowers withbed knives or shear plates. Some dulling of the blades may beacceptable, and is commonly tolerated in practice due to the troubleand/or expense involved in keeping the blades sharp. Nevertheless, sharpblades are desirable for best performance.

Various types of sharpeners have been suggested, particularly forconventional reel mowers. Some are attachments which must be manuallymounted on the mowers. Others are mounted on the mower and manuallymoved into sharpening position. Both types require manipulation by theuser, and some degree of care and attention, and widespread use has notbeen attained. In the case of rotary mowers, it is common to remove theblades from the machine for sharpening, or to employ special grindingwheels in a power tool.

In my U.S. Pat. No. 3,659,385, a sharpening attachment is described formowers of the cross-flow type. Since this also requires manipulation, auser may not go to the trouble of keeping the blades sharp, even if theattachment is provided.

SUMMARY OF THE INVENTION

The mower of the present invention includes a sharpener whichautomatically sharpens the blades each time the clutch between motor androtor is disengaged, and at the same time serves to brake the rotor.Accordingly, the term "brake/sharpener" is used. To this end, one of thewall sections of the blower conduit extending laterally along the lengthof the rotor has an abrasive panel facing the rotor, and the abrasivepanel is mounted for movement between a mowing position in which thepanel is spaced from the rotor and a brake/sharpener position in whichthe panel is contacted by the blades. Means are provided forautomatically moving the abrasive panel to its brake/sharpener positionwhen the clutch is disengaged, and to its spaced mowing position whenthe clutch is engaged.

Accordingly, each time the operator disengages the clutch, the bladesare sharpened by the abrasive panel and the abrasive panel slows therotation of the rotor to a halt.

The brake/sharpener may be used with either direction of rotation of therotor. However, as stated above, in the preferred arrangements thedirection of rotation is such that the lower blades move in the normallyforward direction of travel of the mower. In such case the blowerconduit has upper and lower wall sections extending laterally along thelength of the reel, and respective portions of the wall sections areclose to the rotor at circumferentially spaced positions separatinginlet and outlet regions of the blower. The abrasive panel may belocated on the upper or lower wall section, advantageously the upperwall section.

The wall section carrying the abrasive panel may be pivotally mounted inthe sides of the housing and moved to either of its two positions by aneccentric rod extending laterally of the mower. To avoid excessiverattle during mowing, however, the upper edge of the wall sectioncarrying the abrasive panel may be resiliently attached to the adjacentportion of the blower conduit and arranged with sufficient flexibilityto allow deflection of the abrasive panel to and away from the rotorblades.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of a mower in which the present invention is used;

FIG. 2 is a bottom view of the mower;

FIG. 3 is a vertical section through the mower;

FIGS. 4 and 5 are detail views of one embodiment of the brake/sharpenerin mowing and brake/sharpening positions respectively;

FIG. 6 is a schematic showing suitable actuating mechanism for thebrake/sharpener of FIGS. 4 and 5;

FIG. 7 is a schematic showing another embodiment of actuating mechanismfor the brake/sharpener; and

FIGS. 8 and 9 are detail views of another embodiment of thebrake/sharpener in mowing and brake/sharpening positions respectively.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS

Referring to FIGS. 1 and 2, the mower carriage includes a top 10, sides11, front and rear frame members 12, 13 and wheels 14. Motor 15 ismounted on top 10 and drives the axle 16 of the rotor through a belt 17(FIG. 3) and pulleys 18, 19. Front wheel drive is provided, but need notbe described. A handle 21 is attached to the carriage in desired manner,and a bag 22 for receiving cut grass may be removably attached.

The rotor is generally designated as 23 and has a blower conduitcooperating therewith to form a cross-flow blower. The rotor may be oneof those shown in application Ser. No. 741,132, or one of those shown inU.S. Pat. No. 3,673,773, or other suitable types. The blower conduit isshown in cross-section in FIG. 3.

Referring to FIG. 3, the blower conduit comprises an upper wall sectionincluding a transversely extending sheet member 24 merging with aportion 10' of the top 10. Member 24 is close to the rotor at 25 and theseparation from the rotor gradually increases toward the rear outletregion 26 of the blower. A lower wall section of the blower conduit isformed by a transversely extending sheet member 27. This also is closeto the rotor, particularly at 28 and 29. In between 28 and 29 the member27 may be curved away from the rotor to promote air flow into the rotorfrom the inlet region 31. This feature will not be described furtherherein, since it is not necessary for an understanding of the presentinvention.

Blades 32 and 33 of the rotor are approximately helical, and are hereshown with forwardly extending outer hooks of the type described in theabove-identified patents. This type is preferred, and the rotor isdriven in the direction indicated by arrow 34 with the blades in theirlower positions moving forwardly in the forward direction of travel ofthe mower. As the blades move, vortex components are producedtherearound which are in one direction of rotation in the inlet regionas shown by arrow 35, and in the opposite direction in the outlet regionas shown by arrow 36.

The action of a cross-flow blower is commonly explained in terms of avortex representing an actual eddy or whirlpool of air at or near theregion where the blades pass from the outlet to the inlet regions. It isbelieved that such a vortex exists at or near the region 30. However theactual configuration is difficult to determine and hence dash lines areemployed. Although this may explain the overall functioning as a blower,for lawn mowing purposes it is believed that the presence of vortexcomponents around the blades is more significant. The vortex actionresults in air being drawn into the inlet region, passing through theopen rotor structure, and then to the outlet region. A curved frontextension 37 in the upper wall of the blower conduit promotes theformation of an auxiliary vortex 38 as described in U.S. Pat. No.3,818,684, supra.

Overall, a major portion of the air flow in the inlet region 31 is atthe lower portion thereof, as indicated by arrow 39, so that there is asubstantial component of velocity tangential to the rotor, and oppositeto the direction of movement of the blades. Thus grass to be cut isforced against the blades, thereby promoting effective mowing. Furtherdetails of the air flow are given in the above-identified patents.

Inasmuch as the vortex components 35,36 around the blades reverse inpassing from the inlet to the outlet region, the portion of upper plate24 adjacent the inlet region may be termed the front vortex breaker, forconvenience. Similarly, inasmuch as the vortices reverse as the bladespass from the outlet region to the inlet region, the lower plate 27 maybe termed the rear vortex breaker.

In the embodiment shown in FIGS. 1-3, a sheet 41 of tough flexiblematerial such as ethylene vinyl acetate (EVA) is placed across the frontof the mower in position to intercept any object which may be hit by theblades and thrown forward. The top of the sheet is advantageouslyattached to a cross bar 42 extending between the links 43 on the ends ofwhich axle 44 for the wheels is mounted. Thus, as the height of themower is adjusted, the lower end of sheet 41 remains close to theground, thereby providing practically complete protection against thrownobjects.

In order to supply sufficient air to the blower despite the blockingaction of sheet 41, a space is provided between the sheet and theforward lip 45 of the housing. Thus air from in front of the mower,indicated at 46, flows over the top of sheet 41, cross bar 42 and axle44, as indicated at 47, and then downward as indicated at 48.

Sheet member 24 is here shown as attached to an arm 49 which is pivotedat 51 to one side of the housing, and to a similar arm at the otherside. The underside of the sheet member 24 is provided with abrasivematerial and the member is pressed against the rotor blades by a cam arm52 each time the rotor is declutched from the driving motor, therebysharpening the blades and also braking the rotor.

In the outlet region, curved plate 53 directes the flow of air towardthe ground, together with cut grass carried thereby, as indicated byarrow 54. Plate 53 is pivoted to the sides of the housing, as indicatedat 55, and may be moved downward when bagging is desired.

Considering now the brake/sharpener in more detail, FIGS. 4 and 5 showthe mechanism of FIG. 3 on an enlarged scale, and in respective mowingand brake/sharpening positions.

Sheet member 24, forming a section of the upper wall of the blowerconduit, has an abrasive panel 60 facing the rotor. The abrasive panelmay be cemented to plate 24, or otherwise affixed therewith. Theabrasive panel and sheet member extend transversely of the mower alongthe entire length of the rotor. Circle 61 indicates the path of travelof the outer edges of the blades which are to be kept sharp. Thedirection is indicated by arrow 62. In the mowing position of FIG. 4,member 24 and abrasive panel 60 are spaced from the rotor in properposition to form the front vortex breaker. The upper edge 63 of member24 is in contact with portion 10' of the top of the mower which forms acontinuation of the blower conduit.

A tubular rod 64 extends transversely of the mower and is eccentricallymounted by arm 52 pivoted at 65 to one side of the mower housing, and bya similar arm pivoted to the other side of the housing. A plurality ofspring tabs or wires, one of which is shown at 66, are attached tomember 24 and spaced transversely of the mower in contact witheccentrically mounted rod 64. In the position of FIG. 4, the spring 66urges the upper edge 63 into contact with top section 10', and allowssome overtravel of rod 64 clockwise to avoid criticalness of adjustment.

In FIG. 5, eccentrically mounted rod 64 has been turned counterclockwiseabout pivot point 65 to press against member 24 and cause the member toturn about pivot point 51 to press the abrasive panel 60 against theouter edges of the rotor blades moving in circular path 61. The centralsection of the abrasive panel has the same radius of curvature as therotor, as indicated at 67 in FIG. 4, so as to provide a substantialsharpening and braking area. The lower edge 68 of the abrasive panel isflatter so that the blade edges do not gouge the panel. The upper edge69 may also be flatter to conform to a desired gradually increasingseparation of the front vortex breaker from the rotor.

With approximately helical blades, the edge of a given blade engages theabrasive panel gradually along the length of the blade, and each pointengages the panel for a substantial circumferential distance. Thecircumferential dimension of the abrasive panel is selected with respectto the helix angles and the blade lengths so that a succeeding blade atsome point along the rotor engages the panel before a preceding bladeleaves the panel. That is, in the brake/sharpening position a portion ofat least one blade is always in contact with the abrasive panel as therotor rotates. This maintains the panel in proper sharpening positionwith respect to the path of travel of the blade tips illustrated bycircle 61,without bouncing.

FIG. 6 illustrates suitable mechanism for actuating the brake/sharpener.A stub shaft 71 extends through the side plate (not shown) of the mowerhousing and is attached to arm 52 so that the rod 64 rotateseccentrically about axis 65. A lever 72 is attached to stub shaft 71.Tension spring 73 yieldingly biases shaft 71 and eccentric rod 64counterclockwise as viewed from the right end, and hence yieldinglybiases abrasive panel 60 to its brake/sharpening position. Lever 72 alsoactuates clutch means comprising idler 74, belt 17 and the associatedpulleys for engaging motor 15 (FIG. 3) with rotor 23, and disengagingthe motor. FIG. 6 shows belt 17 in partial view. An idler 74 is carriedby arm 75 pivoted at 76 to the mower housing. Spring 77 connects arm 75with lever 72. Lever 72 is actuable by a cable 78 connected to asuitably located lever, such as a so-called deadman's control.

When cable 78 is tightened by the user, lever 74 is turned clockwiseand, through spring 77, the idler 74 is pulled against belt 17 totighten the belt around pulley 19 on the rotor axle. Accordingly, themotor drives the rotor. At the same time, the turning of lever 72 moveseccentric rod 64 away from the rotor, and, through springs 66, moves thebrake/sharpener away from the rotor to its mowing position shown in FIG.4. When cable 78 is loosened, spring 73 turns lever 72 counterclockwise,thus loosening idler 74 and belt 17 to disengage the motor from therotor pulley 19, and at the same time moving plate 24 and abrasive panel60 to its brake/sharpening position shown in FIG. 5.

As will be understood, each time the operator releases cable 78, theblades are sharpened and the rotor braked. If the number of actuationsduring normal use do not keep the blades sufficiently sharp, or portionsof the blades are dulled by contact with debris, the clutch may beengaged and disengaged a number of times in succesion to repeat thesharpening operation.

FIG. 7 shows another embodiment of mechanism for actuating thebrake/sharpener of FIGS. 4 and 5. Here, however, the eccentricallymounted rod 64 is mounted to pivot around an axis 81 which is above therod so that the turning directions are interchanged. That is, clockwiserotation as viewed from the left engages the brake/sharpener with therotor and counterclockwise rotation releases it.

Tension springs 82 are attached to short lever arms affixed to the endsof rod 64 to resiliently bias the rod clockwise, thus pressing the rodagainst plate 24 to engage the brake/sharpener with the rotor blades.Lever arm 72 is affixed with the eccentrically mounted rod 64 as before,and the wire core 78 of an actuating cable is attached to one end oflever arm 72. The cable sheath 78' is attached to handle 21 of themower, and the upper end of the wire core 78 is attached to a deadman'scontrol arm 84 which is pivoted on the handle as shown by line 85. Whenthe control arm 84 is pulled against the top of handle 21, wire core 78is tightened and turns lever arm 72 counterclockwise. This moveseccentric rod 64 back from plate 24, and spring fingers attached toplate 24 and engaging rod 64 (one of which is shown at 76) moves plate24 away from the rotor to its mowing position as shown in FIG. 4.

A rigid rod 87 connects the other end of lever arm 72 with an idleractuating plate 88. Plate 88 and idler arm 75 are pivoted about axis 89,and are interconnected by spring 90. When wire core 78 is tightened, rod87 rotates plate 88 clockwise and, through spring 90, rotates idler arm75 clockwise to press idler wheel 74 against belt 17. Thus the belt istightened around pulleys 18 and 19 and the motor drives the rotor. Whencontrol lever 84 is released, springs 82 cause lever arm 72 to turnclockwise, thus turning plate 88 counterclockwise and relieving thetension on idler arm 75 and thereby the tension of belt 17. Accordingly,the motor is disengaged from the rotor, and the brake/sharpener stopsthe rotor and at the same time sharpens the blades.

This design allows substantial overtravel of eccentric rod 64 andactuating plate 88 to eliminate critical adjustments. When wire core 78is tightened to disengage the brake/sharpener from the rotor, the upperedge 63 of plate 24 engages the top of the mower as seen in FIG. 4.Further movement of eccentric rod 64 is allowed by finger springs 76.Overtravel of plate 88 is allowed by spring 90 without excessivelyincreasing the force of idler wheel 74 on belt 17. To keep the forcewithin desired limits, spring 90 is attached to plate 88 and idler arm75 so that, as the spring elongates, it moves closer to pivot axis 89.Thus the angle at which spring 90 pulls on arm 75 decreases and theresultant rotating force on arm 75 increases very slowly.

In some cases, such as with the rotors of Ser. No. 741,132 having twoblades per section, air pulsations may cause the brake/sharpener ofFIGS. 4 and 5 to rattle during mowing. This may occur at point 63, andat the pivot points which may wear during use. The embodiment of FIGS. 8and 9 is designed to eliminate any such rattling.

Referring to FIGS. 8 and 9, sheet section 91, forming the front vortexbreaker, is fastened along its trailing edge to the housing withinterposed rubber washers 92 and rivets, bolts, etc. The leading edge issecured, as by welding, to struts attached to the sides of the housing,one of which is shown at 93. The struts are also attached to the housingwith rubber washers or grommets. Extension 37 for the auxiliary vortexin front of the rotor may be provided. The section 91 is channeled toreceive the abrasive panel 94 which extends transversely along thelength of the rotor. Eccentric rod 64 is pivoted at 95.

FIG. 8 shows the brake/sharpener in mowing position, with section 91 andabrasive panel 94 spaced from the rotor. In FIG. 9, eccentric rod 64 hasbeen turned clockwise to press abrasive panel 94 against the blade edgesof the rotor, the resiliency of the rubber washers 92 and that of sheetsection 91 allowing sufficient movement. When rod 64 is subsequentlyturned counterclockwise, the resiliency returns section 91 and panel 94to the position of FIG. 8.

In the mowing position, preferably the eccentric rod 64 is out ofcontact with sheet section 91, as illustrated in FIG. 8. This, togetherwith the attachment of the leading and trailing edges to the housing,and a small spacing of the side edges of section 91 from the sides ofthe housing, eliminates objectionable rattle during mowing.

The actuating mechanism of FIG. 7 may be used to control the rotation ofrod 64 of the brake/sharpener of FIGS. 8 and 9.

Other arrangements are possible for mounting the vortex breaker andassociated abrasive panel and moving them toward and away from therotor. For example, instead of attaching the leading edge of plate 91 tostruts 93, a transverse tube could be welded at the junction of theleading edge and the auxiliary vortex forming section 37. A rod with camwashers spaced therealong could then be inserted in the tube and the rodturned to move the abrasive panel toward and away from the rotor, theresilience of plate 91 and rubber washers 92 allowing sufficientmovement.

In sharpening, some sparks will commonly be generated. With the abrasivepanel on the front vortex breaker, as in the specific embodimentsdescribed, the sparks will be dissipated inside the housing. This isfacilitated by the decrease in blower action when the front vortexbreaker contacts the rotor. With this arrangement, the rear vortexbreaker may be designed without regard to brake/sharpeningconsiderations, and visible hot sparks avoided. However, if desired, therear vortex breaker could be designed as a brake/sharpener and arrangedto move toward and away from the rotor.

Sheet metal construction has been shown in the specific embodiments.However, plastics may be employed if desired.

I claim:
 1. A mower of the cross-flow blower type comprising(a) acarriage, (b) a cylindrical rotor mounted on said carriage with the axisthereof substantially horizontal and extending laterally of thecarriage, (c) said rotor having one or more sections along the axisthereof with a plurality of circumferentially-spaced approximatelyhelical fixed blades in each section moving in the same path of traveland spaced from the rotor axis to leave the major portion of theinterior of the rotor free for air flow through the rotor transverselythereof, (d) motor means for driving said rotor, (e) the outer leadingedges of the blades being sharp to form cutting edges and thecross-section of the blades having at least a portion on the leadingside thereof which slopes backwardly and inwardly with respect to thedirection of rotation of the rotor, (f) a blower conduit cooperatingwith said rotor to form therewith a cross-flow blower, (g) said conduitcomprising two wall sections extending laterally along the length of therotor and having respective portions close to the rotor atcircumferentially spaced positions separating inlet and outlet regionsof the blower, (h) said inlet region opening downwardly and forwardlywith a portion of the rotor therein exposed to material to be mowed, (i)the portions of the mower adjacent the rotor being non-shearingly spacedfrom the path of travel of said blades during moving operation, (j)clutch means for engaging said motor means with said rotor anddisengaging the motor means therefrom, (k) one of said wall sections ofthe conduit having an abrasive panel facing said rotor, (l) meansmounting said abrasive panel for movement between a mowing position inwhich the panel is spaced from the rotor and a brake/sharpening positionin which the panel is contacted by the rotor blades, (m) and means forautomatically moving said abrasive panel to said brake/sharpeningposition when said clutch means is disengaged and to said mowingposition when the clutch means is engaged.
 2. A mower according to claim1 in which said abrasive panel forms at least a part of one of saidportions of the wall sections close to the rotor.
 3. A mower of thecross-flow blower type comprising(a) a carriage, (b) a cylindrical rotormounted on said carriage with the axis thereof substantially horizontaland extending laterally of the carriage, (c) said rotor having one ormore sections along the axis thereof with a plurality ofcircumferentially-spaced approximately helical fixed blades in eachsection moving in the same path of travel and spaced from the rotor axisto leave the major portion of the interior of the rotor free for airflow through the rotor transversely thereof, (d) motor means for drivingsaid rotor in a rotational direction such that the lower blades move inthe normally forward direction of travel of the mower, (e) the outerleading edges of the blades being sharp to form cutting edges and thecross-section of the blades having at least a portion on the leadingside thereof which slopes backwardly and inwardly with respect to thedirection of rotation of the rotor, (f) a blower conduit cooperatingwith said rotor to form therewith a cross-flow blower, (g) said conduitcomprising upper and lower wall sections extending laterally along thelength of the rotor and having respective portions close to the rotor atcircumferentially spaced positions separating inlet and outlet regionsof the blower, (h) said inlet region opening downwardly and forwardlywith a portion of the rotor therein exposed to material to be moved, (i)the portions of the mower adjacent the rotor being non-shearingly spacedfrom the path of travel of said blades during mowing operation, (j)clutch means for engaging said motor means with said rotor anddisengaging the motor means therefrom, (k) one of said upper and lowerwall sections having an abrasive panel facing the rotor, (l) meansmounting said one wall section for movement between a mowing position inwhich the abrasive panel is spaced from the rotor and a brake/sharpeningposition in which the panel is contacted by the rotor blades, (m) andmeans for automatically moving said abrasive panel to saidbrake/sharpening position when said clutch means is disengaged and tosaid mowing position when the clutch means is engaged.
 4. A moweraccording to claim 3 in which said abrasive panel forms at least a partof the portion of the upper wall section which is close to the rotor. 5.A mower according to claim 4 in which said means for moving the abrasivepanel includes an eccentrically mounted rod extending laterally of themower, lever means for turning the rod toward said one wall section andaway therefrom, and means for yieldingly biasing said rod toward saidone wall section.
 6. A mower according to claim 4 in which the trailingedge of said upper wall section is resiliently attached to the adjacentportion of the blower conduit.